Polyhedral TiO2 particle-based cathode for Li-S batteries with high volumetric capacity and high performance in lean electrolyte

Abstract

Achieving high volumetric capacity in Li-S batteries featuring light weight opens up unique applications. To address this, we demonstrate a high tap-density cathode based on polyhedral TiO2 (poly-TiO2) particles. The poly-TiO2 particles are obtained by fracturing 3D ordered macroporous TiO2 structure. Poly-TiO2 particles achieve high packing densities by assembly of surface-to-surface contact. Compared to commercial TiO2 nanoparticles, poly-TiO2 exhibits an apparent tap-density of about 6 times higher. We prepare a Li-S battery with a poly-TiO2 particle-assembled film as the host of the sulfur. The poly-TiO2 particle cell exhibits a volumetric capacity of 1145 mAh/cm3, which is about 9 times higher than the TiO2 nanoparticle cathode cell. The poly-TiO2 cathode with high tap-density shows excellent performance in lean electrolyte condition. Under extremely lean electrolyte conditions with an E/S value of 2.8, the poly-TiO2 cell exhibits a high capacity of 607 mAh/g at 1C-rate.